Taking Tests Answers

When potassium iodide liquid is poured into lead nitrate solution (both clear solutions), a bright yellow solid, lead iodide, forms in a potassium nitrate solution. What are the signs that this is a chemical reaction? Check all that apply.

A food item that is left out of the refrigerator turns brown and forms bubbles and gas. What are the signs that this is a chemical reaction? Check all that apply.Heat is produced.Heat is absorbed.Bubbles appear.A precipitate forms.The color changes.

Pure sodium metal placed in water will spark and ignite, as well as form bubbles and gas. What are the signs that this is a chemical reaction? Check all that apply.Heat is produced.Light is produced.Heat is absorbed.Bubbles appear. A precipitate forms.The color changes.